The present invention relates to a photosensitive member having a surface protective layer, and more particularly to a photosensitive member having specks as a surface protective layer.
There are proposed various photosensitive layers composed of inorganic photoconductive substances such as selenium or organic photoconductive substances for use in electrophotographic photosensitive members. In general photosensitive layers having low hardness tend to be abraded or scratched by the friction with transfer papers, cleaning members, developers and the like during repeated copying operations.
From the above mentioned problem, there is proposed to provide a surface protective layer for a photosensitive member having insufficient hardness.
There are known amorphous silicon photosensitive layers excellent in hardness and abrasion resistance. However, it is to be noted that surface protective layers are also provided on the amorphous silicon photosensitive members to improve the surface characteristics.
Furthermore, when coherent monochromatic light such as a laser beam is employed as a light source for exposure to form electrostatic latent images, there may occur a problem that each light reflected from the uppermost surface of a photosensitive member, from each interface between the respective layers constituting the photosensitive member, and from the interface between the substrate and the photosensitive layer may interfere with one another. The longer the wavelength of the laser beam is, the more remarkable the interference phenomenon is, because the adsorption of the laser beam into the photosensitive layer is decreased.
Still furthermore, with respect to the thickness of the photosensitive member or of the respective layers constituting the photosensitive member, irregularities of such a degree as submicron (which corresponds to the wavelength of laser beams) are formed inevitably by any conventional layer-forming method.
Accordingly, the interference phenomena and the uneveness in the thickness of the photosensitive member inevitably cause interference fringes in the copied images formed on the photosensitive member, resulting in poor image reproduction.
This problem can not be solved merely by forming a surface protective layer on the photosensitive member.